BORON

The element

The single nonmetallic element in group 13, boron consist a strong tendency to covalent bonding. Its exclusively complex structural chemistry occurs from the (2s)²(2p)¹ configuration, that gives it one less valence electron than the number of orbitals within the valence shell. Simple compounds like BCl₃ have a not complete octet and are strong Lewis acids, but boron frequently accommodates its electron deficiency through forming clusters with multicenter bonding.

Boron is an not a common element on the Earth overall (about 9 p.p.m. in the crust) but take place in concentrated deposits of borate minerals like borax Na₂[B₄O₅(OH)₄].8H₂O, frequently related with former volcanic activity or hot springs. It is employed widely, mostly as borates in glasses, cosmetics, detergents and enamels, and in lesser amounts in metallurgy. Boron is not frequently required in its elemental form, but it can be get through electrolysis of fused salts, or through reduction either of B₂O₃ with electropositive metals or of a halide with dihydrogen, the last technique giving the purest boron. The element has several allotropic structures of enormous complexity; their dominant theme is the existence of icosahedral B₁₂ units connected in dissimilar ways. Multicenter bonding models are needed for interpret these structures.